Let's face it, whenever you buy a gadget like the iPhone, iPad or iPod touch, you envision one or two Really Cool Things you'll happily do with it. Otherwise why buy the gadget in the first place?

The HBO Go app for Apple's iOS-based devices is definitely a Really Cool Thing, streaming in a selection of HBO's movie catalog as well as a wide range of past and current programming (The Sopranos, True Blood, Boardwalk Empire, Six Feet Under, etc.) over both 3G and Wi-Fi networks.